Method and apparatus for adjustable metering

ABSTRACT

The present invention relates to metal metering methods and apparatus such as employed in welding equipment using granular material to form its weld bead; and more particularly, relates to such metering methods and apparatus and the controls therefor. The present invention encompasses the use of methods and control means to provide controlled rates of feed for the granular material, either based on the rate of feed of the electrode or on selected compositions for the weld bead. In addition to the basic method disclosed, a mechanical embodiment of the apparatus is shown which employs a rocker arm or arms and a linkage to transfer motion from a shaft connected to the electrode feed means to the metering wheel. Adjustment is provided for the rocker arm and linkage to adjust the amount of motion that is transferred to each individual metering wheel. An electrical embodiment of the apparatus is also disclosed and this utilizes two controls to limit the current flow to the metering wheel motors, one to adjust the current flow in relation to the rate of feed for the electrode and the second to provide individual control over individual motors, and in turn, over individual metering wheels. The present invention, therefore, provides method and means to give, not only synchronization of the granular feed with the electrode feed, but also over the composition of the total feed by controlling the rate of feed of the individual ingredients.

United States Patent 91 Arnoldy [451 May 22, 1973 METHOD AND APPARATUSFOR ADJUSTABLE METERING [75] Inventor: Roman F. Amoldy, Houston, Tex.

[73] Assignee: R. 1. Patents, Inc., Houston, Tex.

[22] Filed: Mar. 4, 1971 [21] Appl. No.: 121,220

Related US. Application Data [62] Division of Ser. No. 849,020, Aug. 11,1969, aban- Primary Examiner-J. V. Truhe Assistant Examiner-L. A.Schutzman Att0rney.lames F. Weiler, Jefferson D. Giller. William A.Stout et al.

[57] ABSTRACT The present invention relates to metal metering methodsand apparatus such'as employed in welding equipment using granularmaterial to form its weld bead; and more particularly, relates to suchmetering methods and apparatus and the controls therefor. The presentinvention encompasses the use of methods and control means to providecontrolled rates of feed for the granular material, either based on therate of feed of the electrode or on selected compositions for the weldbead. In addition to the basic method disclosed, a mechanical embodimentof the apparatus is shown which employs a rocker arm or arms and alinkage to transfer motion from a shaft connected to the electrode feedmeansto the metering wheel. Adjustment is provided for the rocker armand linkage to adjust the amount of motion that is transferred to eachindividual metering wheel. An electrical embodiment of the apparatus isalso disclosed and this utilizes two controls to limit the current flowto the metering wheel motors, one to adjust the current flow in relationto the rate of feed for the electrode and the second to provideindividual control over individual motors, and in turn, over individualmetering wheels. The present invention, therefore, provides method andmeans to give, not only synchronization of the granular feed with theelectrode feed, but also over the composition of the total feed bycontrolling the rate of feed of the individual ingredients.

23 Claims, 9 Drawing Figures PATENTE umzzlsra SHEET 3 []F 3 METHOD ANDAPPARATUS FOR ADJUSTABLE METERING CROSS-REFERENCES TO RELATEDAPPLICATIONS This application is a divisional application of mycopending application Ser. No. 849,020, filed Aug. 11, 1969, nowabandoned, entitled Method and Apparatus For Adjustable Metering.

BACKGROUNDOF THE PRESENT INVENTION This invention pertains to the fieldof metering materials, whereby the metering operation can be controlled;and more particularly, metering and control method and apparatustherefor, which are to be used in electric arc welding in which the weldbead is comprised of melted metal from a consumable electrode and fromalloy granules.

This last described type of electric arc welding is oftentimes referredto as bulkwelding and is generally disclosed in my U.S. Pat. No.3,076,888, issued Feb. 5, 1963, and entitled Method of Producing WeldCoatings or Fusion Welds, which patent illustrates several examples ofbulkwelding. Furthermore, my US. Pat. Nos. 3,172,991 and 3,296,408illustrate additional techniques which may be used in bulkwelding andapparatus to accomplish these techniques.

Generally, this bulkwelding is accomplished by the continuous supply ofa consumable electrode to the welding zone while at the same timesupplying a selected mixture of granular material or materials(hereinafter sometimes referred to as granular). The weld bead oroverlay is formed by the melting of the material in the granular, theelectrode, as well as a portion of the base metal onto which the bead isdeposited. An overlay or bead of a desired composition may be achievedby varying the amounts of electrode or granular that is fed into theweld zone. Furthermore, it is often desirable to adjust the mix ofmaterial during operation and it would be desirable to have method andmeans to accomplish this readily and easily. In addition, where severalgranular materials are being used, it is also desirable to be able toadjust the rate of feed of one granular material independently of therates of feed of the other granular materials or of the electrode.

Furthermore, in automatic arc welding and particularly in weldoverlaying, the quality of a deposited bead and the exact analysis ofthe deposited metal is difficult to predict. This is true because theamount of dilution by the base metal cannot be accurately forecast, andit varies with the analysis and thickness of the workpiece and with thecurrent, voltage and travel speed of the operation, as well as with thefluxing agent used and the viscosity of the molten metal. Furthervariation results because some elements are burned out in the arc andothers are absorbed by the flux while still others may be added. Forthese reasons, the conditions required to produce a given weld arealways determined empirically and such determinations must be maderepeatedly. Furthermore, these conditions cannot be exactly repeatedwith reliability from job to job or even from day to day.

In materials of critical composition, special electrodes are usuallymade up with compensated compositions, and special fluxes are used whichcontain metal addition to compensate for the losses expected. After theneed is detennined, considerable time is required to make up theelectrodes needed and/or the fluxes. After perhaps several trials, thenecessary combination of electrodes, flux and welding conditions areobtained to produce the alloy balance required in the deposit.

Unfortunately, these conditions do not tend to remain balanced. Theworkpiece may be different enough in composition from the test platethat the fluidity is changed, which changes the penetration anddilution, upsets the balance and produces an unsatisfactory deposit.Differences in trace element content can cause this effect. Also,different lots of fluxes will behave differently, and thus, produce thesame effect. Different lots of electrode materials will vary incomposition enough to upset the balance required and change the depositobtained.

Prior to the present invention, apparatus have been unavailable by whichthe composition of the alloy granular material could be varied asdesired. Operators were, therefore, limited in making changes incomposition to having different electrodes made up, or fluxes prepared.These operations were time consuming and resulted in delay and possiblesubstantial expense.

SUMMARY OF THE PRESENT INVENTION The present invention utilizes meteringmethod and apparatus which accurately meter the granular to the weldzone, and which includes adjusting the rate of feed of each individualmetering station to achieve the desired composition, along with methodand means to automatically accomplish adjustments in the overall feed ofthe granule material relative to changes in the rate of feed of theconsumable electrode.

The method involved teaches basically the provision of a welding methodwhich includes the steps of feeding a consumable electrode to a weldzone at a predetermined rate of feed; metering a granular material ormaterials onto the base metal at the weld zone to provide the otheringredients desired in the weld bead; and adjusting, during the weldingoperation, the rates of feed of the granular with adjustments in therate of electrode feed, or independently thereof as desired to adjustthe weld bead composition. In addition periodic testing of the bead andreadjusting of the feed is included to provide the necessaryquality'control.

Two presently preferred apparatus embodiments are disclosed herein. Thefirst embodiment discussed in the mechanical embodiment and thisutilizes one or more rocker arms cooperating with gear means whose rateof rotation varies with the rate of the electrode feed. The rockingmotion produced in the rocker arms by the toothed gear means istransmitted to a metering wheel which feeds or meters the granular.Clutch means are provided so that the rocking motion is transmitted tothe metering wheel shaft in one direction only, thus causing the wheelto rotate in only one direction of rotation. As will be understood, asthe electrode feed changes speed, a corresponding change in speed willoccur in the gear means and the rocker arm. Thus, the feed of thegranular is synchronized with the electrode feed.

Further adjustment is provided by means of adjustable screw means whichchanges the position of the' rocker arm-linkage means relative to theconnection through the clutch means to the metering wheel. This changein position also changes the amount of the rocking motion from therocking arm that is transmitted through the linkage to the wheel.Accordingly, means are provided to change the rate of feed of thegranular, not only in response to a change in the rate of feed of theelectrode, but also to change the rate of feed of the granularindependently of the rate of electrode feed.

This same control is provided by the second embodiment disclosed whichutilizes electrical control means. This embodiment employsvariable-speed, electric motors to drive the metering wheels which meterthe granular materials. Switch means are provided which monitor andcontrol the amount of current allowed to the motors, thereby controllingthe speed of the meters, and in turn, the speed of the metering wheels.These switches are in turn controlled by signals transmitted throughappropriate circuitry.

These signals are produced firstly, by an appropriate operativeconnection with the electrode feed means so that the signal increases asthe speed of the electrode feed means increases and vice versa.Furthermore, individual controls are contained in the circuit for eachmotor to provide individual control of the signal independently of theelectrode feed.

It is, therefore, an object of the present invention to provide methodand means by which granular material may be metered through a meteringwheel and which will provide accurate and easily performed adjustmentsin this rate of feed.

Another object of the present invention is to provide such meteringmethod and apparatus for metering the respective granular materials at apredetermined rate dependent upon the rate of feed of an electrode, andfor adjusting the rate of feed of the granular as the electrode feedrate varies so as to maintain the proper proportions.

Still another object of the present invention is to provide suchmetering methods and apparatus, whereby the rate of feed of the granularmay be controlled independently of the electrode feed rate, as well asof the feed rate of the other granular materials.

Still another object is to provide such methods which will be simple andeasy to perform, yet which will give a high degree of control andaccuracy over the weld being produced thereby.

An additional object is to provide such metering apparatus and thecontrols therefor which will be relatively inexpensive to manufactureand operate, that will be relatively small in size so as to be carriedin a weld head and to be accurate in its metering function and theadjustments thereof.

Another object of the present invention is to provide such apparatuswhich will provide long service life, and due to its relativesimplicity, will be relatively maintenance free.

Other and further objects, features and advantages will be apparent fromthe following description of the presently preferred embodiments of theinvention, given for the purpose of disclosure, when taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the attached drawings, likecharacter references designate like parts throughout the several views,which views are as follows:

FIG. 1 is a side elevation view partially illustrating a weld head intowhich the present invention may be incorporated,

FIG. 2 is a top plan view, partially in section, showing the presentinvention as seen along Section Lines 2--2 of FIG. 1,

FIG. 3 is a side elevation view as seen along Section Lines 3-3 of FIG.2,

FIG. 4 is a side elevation view of the apparatus shown in FIG. 3, butwith the rocker arm and linkage means in a different position from FIG.3,

FIG. 5 is a side elevation view of the apparatus of FIGS. 3 and 4, butwith the individual control means in a second position from that ofFIGS. 3 and 4,

' FIG. 6 is a partial top view, in section, as seen along Section Lines6.6 of FIG. 3,

FIG. 7 is a side elevation view of the present invention as seen alongSection Lines 7-7 of FIG. 2,

FIG. 8 is a perspective view of the second embodiment of the presentinvention, partially in section and partially exploded, and

FIG. 9 is a schematic view of an electrical circuit which may beutilized with this second embodiment.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS For purposes ofdisclosure, the present invention will be described as applied in anautomated weld head used in a bulkwelding operation. Although this isthe primary application of this invention by far, it is to be understoodthat the invention claimed herein may be used in other applicationswhere such coordination of the metering functions along with individualadjustment thereof is desired.

Turning now to FIG. 1, there is partially shown a weld head 10containing therein the present invention generally indicated at 12. Theweld head 10 moves over a base metal 14 onto which the weld bead oroverlay is applied. A consumable electrode 16 is fed into the weld zone18 at a predetermined rate. The alloy granular mix 20 is laid upon thesurface of the base metal 14 from the funnel 22. In addition, a flux 24is applied on top of the granular by tube 25.

This welding operation is now well known, but I briefly, the electricarc created between the electrode 16 and the base metal 14 creates aweld zone 18 which causes a fusing of the electrode material with thegranular material as well as with a portion of the material making upthe base metal. This forms a solidified or fused bead 26. The flux or atleast a portion thereof is also fused or solidified as at 28. Thissolidified flux is later removed leaving the overlay 26.

Turning now to FIGS. 2-7, the first embodiment utilizing mechanicalcontrol means is disclosed. This particular embodiment shown is made upof three basic components carried in a housing 13. The first componentis the electrode feed and adjustment means and is generally indicated bythe numeral 30. The second component comprises the metering apparatusand control means therefor for a first granular to be used in theprocess. This second component is indicated generally by the numeral 32.The third and final component is a second metering apparatus and controlmeans therefor, and this is indicated generally by the numeral 34. Itshould be understood at the outset that any number of metering apparatusand control means may be utilized with any one electrode feed. Thiswould depend upon the number of ingredients to be included in thegranular mix which is to be introduced at the weld zone.

Discussing first the electrode feed means, reference should be made toFIGS. 2 and 7. It should be noted that in most embodiments, theapparatus now to be described does not actually feed the electrode, butinstead is driven by the electrode which is driven by conventional meansnot shown. This disclosed apparatus may, however, if desired, be poweredand be the actual driving means for the electrode. It should also bepointed out at this point that although a wire electrode is shown, thisinvention may be used with other continuously fed, consumableelectrodes, such as strip electrodes, tubes filled with granularmaterial, and the like.

The electrode feed means is comprised of a first wheel or cam 36 mountedon a shaft 38. An opposed cam 40 forms a nip 42 with the cam 36. Thissecond cam 40 rotates about a shaft 43 which shaft is secured to a bar44 which is pivotally mounted about a shaft 46. A bar 48 is acted uponby the spring 50 to urge the cam 40 against the first cam 36 so that aproper pressure is maintained on the electrode to insure the properrotation of the cam 36 and shaft 38. A knob 52 is threaded to thehousing 13 and is available to vary the force ex erted by the spring 50against the second cam 40. In this way, the speed of the second cam 36will be maintained at a proper relationship with the rate of feed of theelectrode 16, varying with variations in the rate of electrode feed.

Turning now to the metering apparatus itself, reference should be madeto FIGS. 2-7. Only one such apparatus will be described, it beingunderstood that each unit is the same and identical reference numeralshave been utilized to illustrate this. This is also true with regard tothe control means for the metering apparatus.

The metering apparatus is comprised basically of a metering wheel 56having a plurality of openings 58 spaced about itsperiphery and mountedon a shaft 57 for rotation therewith. This metering wheel is positionedwithin a hopper 60 into the rear of which is fed the granular materialthrough a tube 62. A second tube 64 extends from the bottom of thehopper 60 in the front portion thereof. This tube 64 leads to the mixhopper 22 (see FIG. 1).

In operation, the metering wheel is rotated by the apparatus to bedescribed below and turns in a counterclockwise direction as viewed inFIG. 7. This causes the granular material in the'hopper to be picked upby the openings 58,'which material is then discharged into the tube 64,and from there, into the mix hopper and ultimately to the weld zone. Byproper selection of the metering wheel, the openings 58 therein and thespeed of rotation of the metering wheel, one can readily see that aproper metering is achieved of the granular fed to the weld zone.

Turning now to the control apparatus which is utilized to impartrotation to the shaft 57 and in turn to wheel 56,.reference will be madeprimarily to FIGS. 2-6. Two toothed gear members 66 and 68 are securedRocker arms 76 and 78 are connected to the plates 70 and 72respectively. These rocker arms are connected by their lowermost ends ina rotatable fashion, and their uppermost ends are free. Each rocker armcarries a protuberance 80 which bears against the peripheral toothedportion of the gears. It should be noted that the rocker arm 76 bearsagainst the gear 66, while the arm 78 bears against the gear 68.

Rotatably connected to the uppermost ends of the rocker arms 76 and 78are the links 82 and 84 respectively. Spring members 86 extend betweenand connect the plates 70 and 72 to the link members 82 and 84, therebyurging the link members, and in turn the rocker arms, toward the gears66 and 68. It is this spring action that maintains the protuberances 80in constant engagement with the toothed peripheral surface of theirrespective gears.

Clutch means 86 and 88, which are conventional apparatus well known tothe industry, are mounted about the wheel shaft 57, and each clutchmeans has an upstanding lug 90 to which is rotatably connected one ofthe link members 82 and 84. These clutch means act in only one directionso that motion transmitted through the clutch means to the shaft 57 willrotate the shaft in to the shaft 38 for rotation therewith. As can bestbe only one direction. Thus, as viewed in FIG. 3, movemerit of the link82 or 84 to the right, or in their actuating stroke, will cause aclockwise rotation to be imparted to the shaft 57. When the line members82 and 84 move to the left in their return stroke, the upstanding lugs90 will rotate in a counter-clockwise direction, but the clutch will notbe engaged with the shaft 57 when rotated in this direction. Thus, thismotion will not be transmitted to the shaft 57. This is, however,conventional, and no further explanation of its operation is believednecessary.

Turning now to the operation of this first embodiment, when the weldingprocess is started, the electrode 16 is fed between the cams 40 and 36,imparting rotation to these cams. This in turn rotates the shaft 38, andthe gears 66 and 68' secured thereon. Because the rocker arms 76 and 78are spring biased so that their protuberances are in constant contactwith the toothed peripheral surface of these gears, a rocking motionwill be imparted to the rocker arms as they pivot about their points ofconnection 79. This rocking motion is, of course, created by theprotuberances 80 riding up and down on the teeth of the gears.

Thus the free end of the rocking members will move back and forthgenerally toward and away from the clutch means on the shaft 57 asviewed in FIG. 3. This back and forth motion will cause the upstandinglugs to reciprocate through-a limiting arc. As previously pointed out,such reciprocal motion by the upstanding lugs in a clockwise direction,as viewed in FIG. 3, will impart rotation to the shaft 57 through theirrespective clutch means. The return stroke, however, will simply resultin the clutch means slipping and no rotation will occur in the shaft 57.

Furthermore, the two rocker arms 76 and 78 will rock in generallyopposite directions due to the offsetting of the gear teeth on the gears66 and 68. Thus, when the rocker arm 67 moves toward the clutch means,the arm 78 will be moving away from it, as seen in FIG. 3. Altemately,the arm 78 will then move toward the clutch means, while the arm 76moves in its return stroke, as shown in FIG. 4. The alternatepositioning of the teeth with resulting alternate motion of the tworocker arms is also clearly shown in FIG. 6. Here the arm 78 hascompleted its return stroke and its protuberance 80 rests in a valleybetween the teeth on gear 68, while the arm 76 has completed itsactuating stroke and its protuberance rides on the crest of a tooth ongear 66.

As will be understood, therefore, this rocking motion imparting therotation to the shaft 57 will cause the metering wheel to rotate in acounter-clockwise direction as viewed in FIG. 7. This will result in thefeeding of the granular into the conduit 64. As will also be understood,as the rate of feed of the electrode increases or decreases, therotation of the shaft 38, and in turn of the gears 66 and 68, willincrease or decrease accordingly. Thus, the motion created in the rockerarms and eventually transmitted to the shaft 57 and metering wheel 56will increase or decrease in the same manner. By these means, therefore,it is seen that, should the welding operation be speeded up or sloweddown by adjusting the rate of speed of the electrode, the rate of speedof the granular materials will be adjusted proportionately, therebymaintaining the proper composition in the weld bead.

Turning now to the means for adjusting the previously described rockerarm-linkage arrangement, a screw 92 is threadedly engaged in the bracket94 for rotation therein. This screw member 92 does not move, however,along its longitudinal axis relative to the bracket 94. A knob 96 isconnected to the screw member 92 for ease of operation thereof. A sleeve100 threadedly engages the screw 92, whereby it will translate along thelength of the screw upon rotation of the screw. This sleeve 100 isconnected to the rigidly se cured plates 70 and 72 at 79 by means of alink 98.

As can be seen by a comparison of FIGS. 3 and 4 on the one hand and FIG.on the other, by rotation of the screw members and translation of thesleeve 100 away from the knob 96, the plates 70 and 72 will rotate aboutthe shaft 38 to a position such as is shown in FIG. 5. When in thisposition, the free ends of the rocker arms 76 and 78 assume a lowerposition on the gears 66 and 68. Thus, the rocking movement imparted tothe free ends would lie more in a vertical plane than in a horizontalplane as it would, for example, in FIG. 3. Where the rocking motionimparted to the links 82 and 84 is primarily in a horizontal plane, asin FIG. 3, the arc through which the upstanding lugs 90 rotate would begreater, as compared to movement imparted primarily or essentially in avertical plane. The greater the arc of the movement of the lugs 90, ofcourse, the greater is the rotation of the shaft 57 and metering wheel56. Where the movement of the free ends of the rocker arms lie more soin a vertical plane, as for example in the position of FIG. 5, the links82 and 84 will merely rotate about their connecting points on the lugs90 to a greater extent than they will actually impart reciproeatingmovement to the lugs 90.

As can be seen from the above explanation and from an examination ofFIGS. 3, 4 and 5, therefore, by rotation of the knob 96, adjustment ofthe sleeve 100 occurs which will cause the plates 70 and 72 to rotateabout the shaft 38. Such rotation will change the position of the rockerarms, thus varying the amount of the rocking motion that is transmittedthrough the links 82 and 84 to the shaft 57. What is accomplished ineffect is that the effective stroke of the rocker arms is adjusted tochange the speed of the meter wheel shaft with respect to the electrodefeed, while maintaining a given relationship to the electrode feed. Thishas the effect of providing individual control means by which theoperator may select the amount of motion or rotation that is to beimparted to each individual metering wheel 56. Thus, close tolerancesand precise variations in the feeding of the individual granularingredients independently of the rate of feed of the electrode 16 areprovided for. This is also accomplished without affecting thesynchronization between the electrode feed and the granular feedmentioned earlier.

The same result can be accomplished by electrical means as shown inFIGS. 8 and 9. Referring now to FIG. 8, there is shown a housingpositioned on one side of which are two metering wheels 112 and 114. Therotation of these metering wheels is brought about by beingconnected tothe shafts 115 of drive motors 116 and 118. The metering wheels are eachpositioned in their individual hoppers 120 into which the granularmaterials are fed by tubes 122. The width of the hoppers 120 issubstantially equal to the widths of the hoppers 120 is substantiallyequal to the widths of the metering wheels 112 and 114, and accordingly,the only manner in which the granular material may pass into a mix orcentral hopper 124 is by action of these metering wheels rotating in thedirection shown by the arrows on each wheel. The tube 126 from the mixhopper 124 leads to the welding zone and supplies the mixed granular tothis zone. A central partition 128 is also located in the mix hopper 124to aid in the proper depositing of the granular material being fed intothis hopper. The electrode feed is not shown in this embodiment, but itis understood that it is positioned within the weld head in the properproximity to this metering apparatus so that it will be fed into thewelding zone in the wellknown manner.

One electrical circuit that may be utilized to control the granular feedis shown in FIG. 9. The connections between the motors .116 and 118 tothe metering wheels 112 and 114 are shown schematically.

A first voltage source 130 is connected to each of the motors throughsilicone control rectifiers 132. These rectifiers change the AC currentfrom the source 130 to DC current to be used by the motors. Eachrectifier has a control terminal 134, as is well known in the art. Asecond voltage source supplies a variable voltage and is connected byappropriate circuitry shown to the control terminal of the rectifiers.This variable voltage from the source 140 is obtained by the twopotentiometers 142 which are mechanically linked as at 144. Thesepotentiometers 142 are operatively connected to a feed from the motorfeeding the electrode or to a feed from a tachometer measuring the rateof feed of the electrode, so that the voltage supplied from the source140 varies in proportion to the changes of the rate of feed in theelectrode. Due to the linkage 144 between the potentiometers, thevoltage varies equally for each of the circuits leading eventually tothe two rectifiers 132.

Accordingly, the voltage supplied to the control terminals 134 acts as asignal current which allows current from the source 130 to flow throughthe rectifiers, thereby actuating the motors 116 and 118. Thus, as theelectrode rate of feed increases, the signal supplied from the source140 will increase with the result of an increased opening of therectifiers to supply additional current to the motors. This willincrease the speed of the motors, thereby increasing the speed ofrotation of the metering wheels 112 and 114. The same is true, ofcourse, with a decrease of the electrode feed, resulting in a decreasedor lessened signal to the rectifiers and a lessening of the speed of therotation of the metering wheels.

From the above, it is seen that electrical controls are provided tosynchronize the metering of the granular with the electrode feed, in thesame manner as the common shaft 38 synchronized the electrode andgranular feeds in the mechanical embodiment discussed previously.

Provision is also made for individualcontrol over the feeding of thevarious granular ingredients used. This is provided by potentiometers146 which are manually controlled by the operator. As will beunderstood, and adjustment of the selected potentiometer 146 will resultin an increase or decrease in the signal to the corresponding rectifier132. This will, in turn, increase or decrease, as the case may be, thepower flowing to the motor controlled by that particular rectifier.

As will be seen, therefore, provision is made for the operator tocontrol the rotation of the individual metering wheels independently ofthe remaining metering wheels, as well as of the rate of feed of theelectrode. Thus, the operator may vary the composition of the granularmix fed to the welding zone without interfering with the synchronizationbetween the rates of granular relative to the rate of electrode feed.The remainder of the circuit contained in FIG. 9 is conventional and nofurther explanation is believed necessary.

Having the described the operation of two preferred embodiments of theapparatus that make up a portion of my invention, the method is moreclearly seen. This method encompasses a bulk welding method whereby asuitable welding head or machine is moved relative to the base metal onthe surface of which the weld bead is to be deposited. Fed from the weldhead is a consumable electrode of any suitable type, such as wire orstrip. This is fed to a weld zone at a predetermined rate which, it iscontemplated, may be adjusted.

Granular material is also fed or metered to theweld zone atpredetermined rates. The types and numbers of granular materials usedfor any particular operation, as well as the rates of feed of each, willvary depending on the bead composition desired. Thus, one operation mayuse only one granular with the electrode, while another may employ twoor more. The use of different granular materials and different numbersof these materials, allows a wide variety of weld compositions withoutmaking up special electrodes for each. At the same time, the adjustmentsdescribed below provide means for maintaining the quality and accuracyof the sought-for composition.

Turning now to these adjustments, the method first teaches the adjustingof each granular feed independently of the electrode feed or of therates of feed of the other granular materials. Secondly, the presentmethod teaches the automatic adjusting of the feeds of each granular toany adjustments that may take place in the rate of electrode feed. Thissecond adjustment insures that the proportion of each granular relative(1 to each other and (2) relative to the electrode will remain constant.The first adjustment allows operator control of the make up of the bead.In line with this, the method also includes the periodic or selectedtesting of the bead composition to insure accuracy and to provide abasis for making individual adjustments to the granular feeds.

Finally, an electric arc is created between the electrode and the basemetal to create the weld bead as has been previously described. Inaddition, flux may be deposited over the deposited granular as necessaryto the successful operation of the method as is more fully explained inmy U. S. Pat. No. 3,076,888.

In conclusion, therefore, it is seen that the present invention and theembodiments disclosed herein are well adapted to carry out theobjectives and obtain the ends set forth at the outset. Certain changescan be obviously made in the method and apparatus without departing fromthe spirit and the scope of this invention. Such changes might include,without limitation, the use of any number of metering and associatedcontrol apparatus, depending upon the number of granular materials to beused in the granular mix. Accordingly, an invention in metering has beendisclosed which provides method and means by which the composition ofthe weld bead can be closely controlled and adjusted. The presentinvention also teaches synchronization between the granular feeds andthe electrode feed so that the composition of the weld bead will notvary even though the speed of the welding operation is changed. At thesame time, the invention allows the operator to selectively controlvarious ingredients that go into the weld bead in the form of granularmaterials, so that the proper composition can be selected quickly andeasily and can be maintained under varying conditions. The presentinvention is, therefore, well adapted to carry out the objects andobtain the ends and advantages mentioned, as well as others inherenttherein.

What is claimed is:

1. Welding apparatus for use in welding with a consumable electrode andgranular material including,

a weld head,

electrode feed means for feeding the consumable electrode to a weld zoneat a predetermined rate of feed,

granular material metering means for feeding at least one granularmaterial to the weld zone in controlled amounts,

linkage means coordinating the rate of feeding of the electrode feedmeans and the rate of feeding of the granular material metering meanswhereby the consumable electrode and the granular material are fed tothe weld zone in coordinated proportional amounts, and

control means operative for varying the coordinated rate of feeding ofthe electrode feed means and the granular material metering means to theweld zone independently of individual changes in the rate of feed of theelectrode and the controlled amounts of granular material.

2. The invention of claim 1 where,

the linkage means includes means responsive to the rate of feed of theconsumable electrode for transmitting motion to the granular materialmetering means.

3. The invention of claim 1 where,

the linkage means includes,

a shaft rotatably carried by the apparatus arranged to rotate inresponse to the feeding of the consumable electrode to the weld zone,

and where, v

the granular feed means includes,

at least one metering wheel arranged to feed the granular material tothe weld zone operatively connected to and driven by the linkage meansinresponse to rotation of the shaft.

4. The invention of claim 3 where,

the linkage means includes,

linkage means for each of said metering wheels operatively connectingsaid wheel to said shaft, whereby the rotation of the shaft impartsmovement to each of the linkage means which movement is transmitted toeach of the metering wheel, and where,

the control means includes,

control means connected to each of the linkage means for adjusting theamount of movement transmitted to each of said metering wheels.

5. The invention of claim 4 wherein the shaft further includes for eachlinkage means,

a toothed gear secured to said shaft for rotation therewith, and eachlinkage means'is further defined as including,

a first plate adjacent said gear and rotatably mounted about the shaft,

a rocker arm rotatably mounted on the first plate and being biasedagainst said gear, whereby rotation of the gear will impart a rockingmovement to said arm,

a free end on said rocker arm,

each metering wheel being mounted on a wheel shaft for rotationtherewith,

a link operatively connecting the rocker arm free end to its respectivewheel shaft, 1

6. The invention of claim 5 wherein each linkage means further includes,i

one way clutch means mounted about the wheel shaft and to which saidlink is connected for imparting movement from said link to said wheelshaft in one direction only.

7. The invention of claim 6 wherein the control means is defined asincluding,

screw means formed to said welding apparatus for rotation relativethereto, and

a sleeve threadedly engaging said screw means for translation along thelength of the screw means upon rotation thereof, said sleeve beingsecured to the first plate, whereby the first plate rotates about theshaft as the sleeve translates along the screw means.

8. The invention of claim 2 wherein said metering means is comprised of,

a metering wheel for feeding each granular material by rotation of thewheel,

a variable speed motor driving each of the metering wheels,

said control means including,

power circuit means for supplying current to each of said motors for theoperation thereof, the speed of the motors varying with the amount ofcurrent supplied,

voltage control means for controlling the amount of current supplied toeach motor, and

signal control means for control of said voltage control means.

9. The invention of claim 8 wherein,

the voltage control means is controlled by signals sent to the voltagecontrol means by the signal producing means, and

the signal control means includes, signal producing means responsive tothe electrode feed means for supplying a signal to the control means inpredetermined proportion to the rate at 5 which the electrode is fed.

10. The invention of claim 9 wherein the signal control means includes,

second control means for individually controlling the rate of rotationof each of the metering wheels.

1 l. The invention of claim 9 wherein including a voltage control meansfor each motor, the signal control means further including,

means connected to said signal producing means for individuallycontrolling the signals sent to each of said voltage control means.

12. Metering equipment for use in welding apparatus utilizing aconsumable electrode and granular materials in its welding processincluding,

means for feeding the electrode to a weld zone at adjustable rates offeed,

a first shaft rotatably connected to said equipment, the rate ofrotation of the shaft varying with the rate of feed of the electrode,

toothed gear means mounted on said first shaft for rotation therewith,

at least one metering wheel to which granular material is supplied, saidmetering wheel feeding said material into a conduit for conveyance tothe welding zone,

a second shaft on which the metering wheel is cured for rotationtherewith,

a first plate freely rotatable on said first shaft,

a first rocker arm rotatably secured to said first plate and biasedagainst said gear means,

a protuberance on the first rocker arm maintained in contact with thegear teeth by said bias, whereby rotation of the gear means will imparta rocking movement to the first rocking arm,

link means for transmitting said rocking movement to the second shaftfor the rotation thereof, and

control means for varying the amount of the rocking movement that istransmitted to the second shaft.

13. The invention of claim 12 wherein said link means is further definedas including,

clutch means on the second shaft for transferring to the second shaftsaid rocking movement in one direction only.

14. The invention of claim 13 wherein said clutch means includes,

' an upstanding arm, and

said link means further includes a link connecting the first rocker armto the upstanding arm.

15. The invention of claim 13 wherein the control a second rocker armrotatably secured to said plate and biased against said gear means,

a protuberance on the second rocker arm maintaining contact with thegear teeth by said bias, whereby rotation of the gear means will impartsimultaneous rocking movements to the first and second rocking arms,this simultaneous rocking movement of the first and second rocker armsbeing in opposite directions relative to each other,

said link means being further defined as link means for transmitting therocking movement of the first and second rocker arms to said secondshaft for the rotation thereof, and

said control means being further defined as control means for varyingthe amount of rocking movement transmitted to said second shaft.

18. The invention of claim 17 wherein,

the gear means includes a gear for each of the first and second rockerarms, said gears being offset relative to each other whereby the gearteeth will produce said opposite rocking movement in the rocker arms.

19. Metering apparatus for use in welding with a consumable electrodeand granular materials to provide a weld including,

a plurality of metering wheels for metering the granular materials to aweld zone by rotation of the wheels,

a variable-speed electric motor operatively connected to and rotatingeach of the wheels,

electrode feeding means for feeding the electrode to the weld zone,

a power circuit for supplying electrical current to each of said motors,

signal producing means responsive to the electrode feeding means forproducing an electrical signal proportional to the rate at which theelectrode is fed to the weld zone,

voltage control means for each motor for controlling the amount ofelectrical current supplied to its respective motor in response to theelectrical signal from the signal producing means, and

second control means individually controlling the rate of rotation ofeach of the metering wheels.

20. The invention of claim 19 wherein the signal producing means isoperatively connected for supplying the same signal or changes in saidsignal to all of said voltage control means.

21. The invention of claim 19 wherein the second control means isfurther defined as,

means connected to said signal producing means for individuallyadjusting the signals sent to the individual voltage control means.

22. The invention of claim 20 wherein the second control means isfurther defined as,

means connected to said signal producing means for individuallyadjusting the signals sent to each of said voltage control means.

23. The invention of claim 19 wherein each of said voltage control meansis defined as including,

switch means for opening the current flow to its respective motor invarying amounts and in selected proportion to the magnitude of thesignal received,

said voltage control means including a control terminal,

said first signal producing means including a,

second voltage source,

a signal circuit for each voltage control means, each of said controlterminals being connected to the second voltage source by its signalcircuit,

signal adjusting means in each of said signal circuits and operativelyconnected to the electrode feeding means for controlling and adjustingthe signal passing to said control terminals, in predeterminedproportion to the rate of feed of the electrode,

said second control means including,

a manually operated control connected to each of said signal circuitsfor individual control of the signal passing through its circuitindependently of the rate of electrode feed.

1. Welding apparatus for use in welding with a consumable electrode andgranular material including, a weld head, electrode feed means forfeeding the consumable electrode to a weld zone at a predetermined rateof feed, granular material metering means for feeding at least onegranular material to the weld zone in controlled amounts, linkage meanscoordinating the rate of feeding of the electrode feed means and therate of feeding of the granular material metering means whereby theconsumable electrode and the granular material are fed to the weld zonein coordinated proportional amounts, and control means operative forvarying the coordinated rate of feeding of the electrode feed means andthe granular material metering means to the weld zone independently ofindividual changes in the rate of feed of the electrode and thecontrolled amounts of granular material.
 2. The invention of claim 1where, the linkage means includes means responsive to the rate of feedof the consumable electrode for transmitting motion to the granularmaterial metering means.
 3. The invention of claim 1 where, the linkagemeans includes, a shaft rotatably carried by the apparatus arranged torotate in response to the feeding of the consumable electrode to theweld zone, and where, the granular feed means includes, at least onemetering wheel arranged to feed the granular material to the weld zoneoperatively connected to and driven by the linkage means in response torotation of the shaft.
 4. The invention of claim 3 where, the linkagemeans includes, linkage means for each of said metering wheelsoperatively connecting said wheel to said shaft, whereby the rotation ofthe shaft imparts movement to each of the linkage means which movementis transmitted to each of the metering wheel, and where, the controlmeans includes, control means connected to each of the linkage means foradjusting the amount of movement transmitted to each of said meteringwheels.
 5. The invention of claim 4 wherein the shaft further includesfor each linkage means, a toothed gear secured to said shaft forrotation therewith, and each linkage means is further defined asincluding, a first plate adjacent said gear and rotatably mounted aboutthe shaft, a rocker arm rotatably mounted on the first plate and beingbiased against said gear, whereby rotation of the gear will impart arocking movement to said arm, a free end on said rocker arm, eachmetering wheel being mounted on a wheel shaft for rotation therewith, alink operatively connecting the rocker arm free end to its respectivewheel shaft,
 6. The invention of claim 5 wherein each linkage meansfurther includes, one way clutch means mounted about the wheel shaft andto which said link is connected for imparting movement from said link tosaid wheel shaft in one direction only.
 7. The invention of claim 6wherein the control means is defined as including, screw means formed tosaid welding apparatus for rotation relative thereto, and a sleevethreadedly engaging said screw means for translation along the length ofthe screw means upon rotation thereof, said sleeve being secured to thefirst plate, whereby the first plate rotates about the shaft as thesleeve translates along the screw means.
 8. The invention of claim 2wherein said metering means is comprised of, a metering wheel forfeeding each granular material by rotation of the wheel, a variablespeed motor driving each of the metering wheels, said control meansincluding, power circuit means for supplying current to each of saidmotors for the operation thereof, the speed of the motors varying withthe amount of current supplied, voltage control means for controllingthe amount of current supplied to each motor, and signal control meansfor control of said voltage control means.
 9. The invention of claim 8wherein, the voltage control means is controlled by signals sent to thevoltage control means by the signal producing means, and the signalcontrol means includes, signal producing means responsive to theelectrode feed means for supplying a signal to the control means inpredetermined proportion to the rate at which the electrode is fed. 10.The invention of claim 9 wherein the signal control means includes,second control means for individually controlling the rate of rotationof each of the metering wheels.
 11. The invention of claim 9 whereinincluding a voltage control means for each motor, the signal controlmeans further including, means connected to said signal producing meansfor individually controlling the signals sent to each of said voltagecontrol means.
 12. Metering equipment for use in welding apparatusutilizing a consumable electrode and granular materials in its weldingprocess including, means for feeding the electrode to a weld zone atadjustable rates of feed, a first shaft rotatably connected to saidequipment, the rate of rotation of the shaft varying with the rate offeed of the electrode, toothed gear means mounted on said first shaftfor rotation therewith, at least one metering wheel to which granularmaterial is supplied, said metering wheel feeding said material into aconduit for conveyance to the welding zone, a second shaft on which themetering wheel is secured for rotation therewith, a first plate freelyrotatable on said first shaft, a first rocker arm rotatably secured tosaid first plate and biased against said gear means, a protuberance onthe first rocker arm maintained in contact with the gear teeth by saidbias, whereby rotation of the gear means will impart a rocking movementto the first rocking arm, link means for transmitting said rockingmovement to the second shaft for the rotation thereof, and control meansfor varying the amount of the rocking movement that is transmitted tothe second shaft.
 13. The invention of claim 12 wherein said link meansis further defined as including, clutch means on the second shaft fortransferring to the second shaft said rocking movement in one directiononly.
 14. The invention of claim 13 wherein said clutch means includes,an upstanding arm, and said link means further includes a linkconnecting the first rocker arm to the upstanding arm.
 15. The inventionof claim 13 wherein the control means is further defined as including,means for adjusting the position of said first plate about the firstshaft.
 16. The invention of claim 15 wherein said adjusting means iffurther defined as including, screw means rotatably secured to themetering equipment, a sleeve rotatably engaging the screw means fortranslation along said screw means upon rotation thereof, said sleevebeing connected to the first plate, whereby said translation of thesleeve rotates the first plate about the first shaft.
 17. The inventionof claim 13 and including, a second plate freely rotatable on saidshaft, a second rocker arm rotatably secured to said plate and biasedagainst said gear means, a protuberance on the second rocker armmaintaining contact with the gear teeth by said bias, whereby rotationof the gear means will impart simultaneous rocking movements to thefirst and second rocking arms, this simultaneous rocking movement of thefirst and second rocker arms being in opposite directions relative toeach other, said link means being further defined as link means fortransmitting the rocking movement of the first and second rocker arms tosaid second shaft for the rotation thereof, and said control means beingfurther defined as control means for varying the amount of rockingmovement transmitted to said second shaft.
 18. The invention of claim 17wherein, the gear means includes a gear for each of the first and secondrocker arms, said gears being offset relative to each other whereby thegear teeth will produce said opposite rocking movement in the rockerarms.
 19. Metering apparatus for use in welding with a consumableelectrode and granular materials to provide a weld including, aplurality of metering wheels for metering the granular materials to aweld zone by rotation of the wheels, a variable-speed electric motoroperatively connected to and rotating each of the wheels, electrodefeeding means for feeding the electrode to the weld zone, a powercircuit for supplying electrical current to each of said motors, signalproducing means responsive to the electrode feeding means for producingan electrical signal proportional to the rate at which the electrode isfed to the weld zone, voltage control means for each motor forcontrolling the amount of electrical current supplied to its respectivemotor in response to the electrical signal from the signal producingmeans, and second control means individually controlling the rate ofrotation of each of the metering wheels.
 20. The invention of claim 19wherein the signal producing means is operatively connected forsupplying the same signal or changes in said signal to all of saidvoltage control means.
 21. The invention of claim 19 wherein the secondcontrol means is further defined as, means connected to said signalproducing means for individUally adjusting the signals sent to theindividual voltage control means.
 22. The invention of claim 20 whereinthe second control means is further defined as, means connected to saidsignal producing means for individually adjusting the signals sent toeach of said voltage control means.
 23. The invention of claim 19wherein each of said voltage control means is defined as including,switch means for opening the current flow to its respective motor invarying amounts and in selected proportion to the magnitude of thesignal received, said voltage control means including a controlterminal, said first signal producing means including a, second voltagesource, a signal circuit for each voltage control means, each of saidcontrol terminals being connected to the second voltage source by itssignal circuit, signal adjusting means in each of said signal circuitsand operatively connected to the electrode feeding means for controllingand adjusting the signal passing to said control terminals, inpredetermined proportion to the rate of feed of the electrode, saidsecond control means including, a manually operated control connected toeach of said signal circuits for individual control of the signalpassing through its circuit independently of the rate of electrode feed.